Drying apparatus



Nov. 27, 1945. B. R. ANDREWS DRYING AFIPARATUS Filed NOV. 17, 1944 2Sheets-Sheet 1 Bernard@ c/iadiewa,

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Patented Nov. 27, 1945 UNITED STATES PATENTv oFFlcE DRYING APPARATUSBernard R. Andrews, Braintree, Mass.

Application November 17, 1944, Serial No. 563.897

(Cl. 34-68l 3 Claims.

This invention relates to a drying apparatus of that type which usesboth radiant heat and circulating air currents for effecting the dryingoperation.

In my U. S. Patent No. 2,071,015 February 16. 1937 there is illustrateda drying apparatus using circulating air currents which is veryeffective in drying cloth or other material in web form and whichcomprises two parallel walls forming between them a drying space throughwhich the cloth or other web material is fed, each wall being providedwith nozzle elements adapted to project high pressure jets of heated airor other gaseous drying medium against the cloth or other web materialat substantially right angles thereto, thereby creating cycloniccirculating air currents which are carried across the face of the cloth.

It is one of the Objects of the present invention to provide a dryingapparatus such as above referred to with novel means for projectingradiant heat against the cloth while it is subjected to the action ofthe air jets. The action of radiant heat is to raise the temperature ofthe cloth or other web material, thereby facilitating the evaporation ofmoisture therefrom, and such radiant heat together with the circulatingair currents produces a more effective drying apparatus.

A further object of the invention is to provide various improvements indrying apparatus of the above type which will be hereinafter describedand set forth in the appended claims,

In the drawings wherein I have illustrated a selected embodiment of myinvention,

Fig. 1 is a longitudinal section through a drying apparatus embodyingthe invention.

Fig. 2 is a cross section on substantially the line 2 2, Fig. 1.

right angles thereto. These nozzle elements I extend transversely acrossthe space 2 and each may conveniently be provided with an elongatednozzle or eduction slot 8 which extends transversely across the space 2and also transversely across the web 5. Means are also provided fordelivering a jet of heated air through each nozzle slot 8, and while anysuitable means for this purpose -may be adopted, yet I have herein shownmeans for this purpose similar to that illustrated in my above-mentionedpatent.

Each wall 3 and 4 is shown as forming one side of a duct which issupplied with heated air under pressure, the duct corresponding to thewall 3 being indicated at 9 and that corresponding to the wall 4 beingindicated at I0. These ducts are connected through a conduit connectionIl to the discharge of a blower or fan I2 so that.` when the fan isoperating, air under pressure will be delivered to each of the ducts 9,l and sheet-like jets of air will be delivered against the welt-throughthe slots 8 of the various nozzle elements "7 The duct II is preferablyprovided with a siiitable heater element I3 by which the air deliveredfrom the fan is heated before it passes into the ducts 9 and` I0.

These ducts 9 and I Il, the conduit II, and the fan I2 areshown asenclosed in a housing I4,

Fig. 3 is an enlarged fragmentary sectional view on the line 3 3, Fig.2.

Fig. 4 is a section on the line 4-4, Fig. 3.

In the drawings the drying space in which the cloth or other webmaterial is dried is indicated at 2, said drying space being defined bytwo opposed parallel walls 3, 4 between which the cloth or other webmaterial 5 to be dried is fed. 'I'his drying space 2 is open at the endsB for the admission and delivery of the web 5 and is also open at thesides.

The walls- 3 and 4 vare provided with nozzle elements indicatedgenerally at 'l which are adapted to deliver heated air under pressureagainst the cloth or other web material 45, said nozzles beingpreferably so disposed that the jets of heated air are delivered againstthe cloth at which will preferably be made of some suitable insulatingmaterial, and the sides of the drying space 2 are open to the interiorof said housing as is also the inlet I5 for the fan I2. The fan willpreferably be operated to deliver air under relatively high pressureinto the ducts 9 and III so that the sheet-like jets of air issuing fromthe nozzles 1 will have a relatively high velocity. As stated above,these jets are delivered against the cloth at substantially right anglesthereto and become converted into cyclonic air currents which move overthe face of the cloth and pass out the open sides of the drying space 2into the housing, and as the inlet forthe blower I2 communicates withthe interior of the housing, there will be a recirculation of the airwithin the housing as described in my above-mentioned Patent No.2,071,015.

For generating and projecting radiant heat against the cloth while it isthus subjected to the action of the circulating air currents, I haveprovided chambers which are located between adjacent nozzles 1, eachchamber having the wall thereof which is exposed to the drying space 2made of some material having good heat conducting properties, such forinstance, as sheet metal. Means are provided for delivering to each ofthese chambers air which is at a temperature considerably higher thanthat which is delivered to the ducts l and Il so that thewalls ot thechambers become relatively hot and thus radiate heat which is receivedby the cloth or other web material.

These chambers may be provided tor in various ways without departingtrom the invention. In the construction herein shown the side walls ofeach two adjacent nozzle elements are connectedby a partition wall Il ofsheet metal which is spaced from the wall ot the corresponding duct t orIl and which forms with said wall a chamber I1 that extends transverselyacross the drying space 2. As stated above, means are provided fordelivering to each oi the chambers i1 air which has been heated to atemperature considerably' higher than that which .is delivered to theducts t and Il with the result that each of the partition walls Il willbe highly heated and will, thereiore, generate radiant heat whichisprojected on to the cloth.

While various ways of providing tor the delivery of the highly heatedair to the chambers 'i may be employed, I have herein illustrated a hotair supply duct il extending longitudinally of each oi' the ducts 0 andIl, said hot air supply ducts being situated opposite the ends of thechambers i'l, the latter opening at one end into said hot air supplyducts as shown at Il in Fig. 4. There is also provided two exhaust ductsIl extending longitudinally of the ducts I and il on the opposite sidethereof from the hot air supply ducts Il, the chambers i1 being open attheir opposite ends into the exhaust ducts It as shown at I i The twohot air supply ducts il, one for each of the ducts l or Il, areconnected through a suitable conduit 2O to the discharge of a blower orfan 2i, and the exhaust ducts il are connected through a conduit 22 tothe inlet of said fan 2|. A heater 23 of any suitable construction isshown as located in the conduit 2l, this heater operating to heat theair delivered from the fan to a relatively high temperature before it isdelivered to the supply ducts Il.

As an example of one way in which this apparatus may be used, it may beassumed that the heater Il would be operated so as to heat the air whichis delivered from the nozzle slots l to about 300 degrees F. while theheater 23 may be operated to heat the air delivered to the chambers ilto about 500 degrees F. 'I'he circulation of this highly heated airvthrough the chambers l1 will heat the partition walls it to a hightemperature and the latter will then become radiant heat generatorswhich will generate radiant heat at a high temperature and project it onto the cloth.

This radiant heat functions to raise the temperature of the cloth to apoint where moisture therein will be rapidly evaporated, the water-vapor thus produced being carried oil' by the circulating air currents.These circulating air currents are also eiIective in preventing thecloth from being overheated or burned by the radiant heat.

While I have referred above to temperatures of 300 degrees F., yet it isto be understood that these mentioned temperatures are for illustrativepurposes only, and that the actual temperature l. A drying apparatus fordrying web material' comprising an elongated chamber, one wall oi whichextends substantially parallel to the web material to be dried and isprovided with a plurality of nozzle elements directed towards saidmaterial, means to maintain said chamber illled with heated air underpressure whereby such air is delivered through said nozzle elementsagainst the web, an imperiorate partition wail'of heat-conductingmaterial connecting each two adjacent nozzle elements thereby formingthere with a hot air chamber, and means to deliver to said hot airchamber air having a temperature considerably higher than that deliveredfrom said nozzle elements, whereby said partition walls become highlyheated and project radiant heat oi.' relatively high temperature againstthe web material.

2. A drying apparatus having two chambers deilning between them a dryingspace through which cloth or other web material to be dried may be fed,the walls oi said chambers which bound said space being provided withnozzle elements directed toward the web material, each oi' which nozzleelements has a nozzle opening in the form of a slot extendingtransversely of the web material, means for maintaining said chamberslled with heated air under pressure whereby such air is deliveredthrough said nozzle slots against the web material, an imperforatepartition wall of heat-conducting material connecting the sides o! eachtwo adjacent nozzle elements and forming therewith a hot air chamber,and means to supply to said chambers air which has been heated to atemperature consider ably higher than that which is delivered throughthe nozzle slots, whereby said partition walls become highly heated andproject radiant heat of relatively high temperature against the cloth.

3. A drying apparatus for drying web material comprising an elongatedchamber, one wall oi.'

which extends substantially parallel to the web material to be dried andis provided with a plurality of nozzle elements directed towards saidweb material, air moving means to maintain said chamber filled with hotair under pressure whereby such air is delivered through said nozzleelements against the web material, an imperiorate partition wall ofheat-conducting material connecting each two adjacent nozzles therebyforming therewith a hot air chamber, a second air moving means connectedto said hot air chambers and adapted to circulate air therethrough, andmeans to heat the air circulated by the second air moving means to atemperature considerably higher than that of the air delivered from saidnozzle elements whereby said partition walls

